How can I convert a character to its ASCII code using JavaScript?
For example:
get 10 from "\n".
This question is related to
javascript
To ensure full Unicode support and reversibility, consider using:
'\n'.codePointAt(0);
This will ensure that when testing characters over the UTF-16 limit, you will get their true code point value.
e.g.
''.codePointAt(0); // 68181
String.fromCodePoint(68181); // ''
''.charCodeAt(0); // 55298
String.fromCharCode(55298); // '?'
While the other answers are right, I prefer this way:
function ascii (a) { return a.charCodeAt(0); }
Then, to use it, simply:
var lineBreak = ascii("\n");
I am using this for a small shortcut system:
$(window).keypress(function(event) {
if (event.ctrlKey && event.which == ascii("s")) {
savecontent();
}
// ...
});
And you can even use it inside map() or other methods:
var ints = 'ergtrer'.split('').map(ascii);
str.charCodeAt(index)
Using charCodeAt()
The following example returns 65, the Unicode value for A
.
'ABC'.charCodeAt(0)
// returns 65
For those that want to get a sum of all the ASCII codes for a string:
'Foobar'
.split('')
.map(x=>x.charCodeAt(0))
.reduce((a,b)=>a+b);
Or, ES6:
[...'Foobar']
.map(char => char.charCodeAt(0))
.reduce((current, previous) => previous + current)
String.prototype.charCodeAt()
can convert string characters to ASCII numbers. For example:
"ABC".charCodeAt(0) // returns 65
For opposite use String.fromCharCode(10)
that convert numbers to equal ASCII character. This function can accept multiple numbers and join all the characters then return the string. Example:
String.fromCharCode(65,66,67); // returns 'ABC'
Here is a quick ASCII characters reference:
{
"31": "", "32": " ", "33": "!", "34": "\"", "35": "#",
"36": "$", "37": "%", "38": "&", "39": "'", "40": "(",
"41": ")", "42": "*", "43": "+", "44": ",", "45": "-",
"46": ".", "47": "/", "48": "0", "49": "1", "50": "2",
"51": "3", "52": "4", "53": "5", "54": "6", "55": "7",
"56": "8", "57": "9", "58": ":", "59": ";", "60": "<",
"61": "=", "62": ">", "63": "?", "64": "@", "65": "A",
"66": "B", "67": "C", "68": "D", "69": "E", "70": "F",
"71": "G", "72": "H", "73": "I", "74": "J", "75": "K",
"76": "L", "77": "M", "78": "N", "79": "O", "80": "P",
"81": "Q", "82": "R", "83": "S", "84": "T", "85": "U",
"86": "V", "87": "W", "88": "X", "89": "Y", "90": "Z",
"91": "[", "92": "\\", "93": "]", "94": "^", "95": "_",
"96": "`", "97": "a", "98": "b", "99": "c", "100": "d",
"101": "e", "102": "f", "103": "g", "104": "h", "105": "i",
"106": "j", "107": "k", "108": "l", "109": "m", "110": "n",
"111": "o", "112": "p", "113": "q", "114": "r", "115": "s",
"116": "t", "117": "u", "118": "v", "119": "w", "120": "x",
"121": "y", "122": "z", "123": "{", "124": "|", "125": "}",
"126": "~", "127": ""
}
To convert a String to a cumulative number:
const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0), 0);
console.log(stringToSum("A")); // 65
console.log(stringToSum("Roko")); // 411
console.log(stringToSum("Stack Overflow")); // 1386
_x000D_
Say you want to generate different background colors depending on a username:
const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0), 0);
const UI_userIcon = user => {
const hue = (stringToSum(user.name) - 65) % 360; // "A" = hue: 0
console.log(`Hue: ${hue}`);
return `<div class="UserIcon" style="background:hsl(${hue}, 80%, 60%)" title="${user.name}">
<span class="UserIcon-letter">${user.name[0].toUpperCase()}</span>
</div>`;
};
[
{name:"A"},
{name:"Amanda"},
{name:"amanda"},
{name:"Anna"},
].forEach(user => {
document.body.insertAdjacentHTML("beforeend", UI_userIcon(user));
});
_x000D_
.UserIcon {
width: 4em;
height: 4em;
border-radius: 4em;
display: inline-flex;
justify-content: center;
align-items: center;
}
.UserIcon-letter {
font: 700 2em/0 sans-serif;
color: #fff;
}
_x000D_
If you have only one char and not a string, you can use:
'\n'.charCodeAt();
omitting the 0...
It used to be significantly slower than 'n'.charCodeAt(0)
, but I've tested it now and I do not see any difference anymore (executed 10 billions times with and without the 0). Tested for performance only in Chrome and Firefox.
You can enter a character and get Ascii Code Using this Code
For Example Enter a Character Like A You Get Ascii Code 65
function myFunction(){_x000D_
var str=document.getElementById("id1");_x000D_
if (str.value=="") {_x000D_
str.focus();_x000D_
return;_x000D_
}_x000D_
var a="ASCII Code is == > ";_x000D_
document.getElementById("demo").innerHTML =a+str.value.charCodeAt(0);_x000D_
}
_x000D_
<p>Check ASCII code</p>_x000D_
_x000D_
<p>_x000D_
Enter any character: _x000D_
<input type="text" id="id1" name="text1" maxLength="1"> </br>_x000D_
</p>_x000D_
_x000D_
<button onclick="myFunction()">Get ASCII code</button>_x000D_
_x000D_
<p id="demo" style="color:red;"></p>
_x000D_
String.prototype.charCodeAt()
can convert string characters to ASCII numbers. For example:
"ABC".charCodeAt(0) // returns 65
For opposite use String.fromCharCode(10)
that convert numbers to equal ASCII character. This function can accept multiple numbers and join all the characters then return the string. Example:
String.fromCharCode(65,66,67); // returns 'ABC'
Here is a quick ASCII characters reference:
{
"31": "", "32": " ", "33": "!", "34": "\"", "35": "#",
"36": "$", "37": "%", "38": "&", "39": "'", "40": "(",
"41": ")", "42": "*", "43": "+", "44": ",", "45": "-",
"46": ".", "47": "/", "48": "0", "49": "1", "50": "2",
"51": "3", "52": "4", "53": "5", "54": "6", "55": "7",
"56": "8", "57": "9", "58": ":", "59": ";", "60": "<",
"61": "=", "62": ">", "63": "?", "64": "@", "65": "A",
"66": "B", "67": "C", "68": "D", "69": "E", "70": "F",
"71": "G", "72": "H", "73": "I", "74": "J", "75": "K",
"76": "L", "77": "M", "78": "N", "79": "O", "80": "P",
"81": "Q", "82": "R", "83": "S", "84": "T", "85": "U",
"86": "V", "87": "W", "88": "X", "89": "Y", "90": "Z",
"91": "[", "92": "\\", "93": "]", "94": "^", "95": "_",
"96": "`", "97": "a", "98": "b", "99": "c", "100": "d",
"101": "e", "102": "f", "103": "g", "104": "h", "105": "i",
"106": "j", "107": "k", "108": "l", "109": "m", "110": "n",
"111": "o", "112": "p", "113": "q", "114": "r", "115": "s",
"116": "t", "117": "u", "118": "v", "119": "w", "120": "x",
"121": "y", "122": "z", "123": "{", "124": "|", "125": "}",
"126": "~", "127": ""
}
If you have only one char and not a string, you can use:
'\n'.charCodeAt();
omitting the 0...
It used to be significantly slower than 'n'.charCodeAt(0)
, but I've tested it now and I do not see any difference anymore (executed 10 billions times with and without the 0). Tested for performance only in Chrome and Firefox.
For those that want to get a sum of all the ASCII codes for a string:
'Foobar'
.split('')
.map(x=>x.charCodeAt(0))
.reduce((a,b)=>a+b);
Or, ES6:
[...'Foobar']
.map(char => char.charCodeAt(0))
.reduce((current, previous) => previous + current)
While the other answers are right, I prefer this way:
function ascii (a) { return a.charCodeAt(0); }
Then, to use it, simply:
var lineBreak = ascii("\n");
I am using this for a small shortcut system:
$(window).keypress(function(event) {
if (event.ctrlKey && event.which == ascii("s")) {
savecontent();
}
// ...
});
And you can even use it inside map() or other methods:
var ints = 'ergtrer'.split('').map(ascii);
You can enter a character and get Ascii Code Using this Code
For Example Enter a Character Like A You Get Ascii Code 65
function myFunction(){_x000D_
var str=document.getElementById("id1");_x000D_
if (str.value=="") {_x000D_
str.focus();_x000D_
return;_x000D_
}_x000D_
var a="ASCII Code is == > ";_x000D_
document.getElementById("demo").innerHTML =a+str.value.charCodeAt(0);_x000D_
}
_x000D_
<p>Check ASCII code</p>_x000D_
_x000D_
<p>_x000D_
Enter any character: _x000D_
<input type="text" id="id1" name="text1" maxLength="1"> </br>_x000D_
</p>_x000D_
_x000D_
<button onclick="myFunction()">Get ASCII code</button>_x000D_
_x000D_
<p id="demo" style="color:red;"></p>
_x000D_
For supporting all UTF-16 (also non-BMP/supplementary characters) from ES6 the string.codePointAt() method is available;
This method is an improved version of charCodeAt which could support only unicode codepoints < 65536 ( 216 - a single 16bit ) .
JavaScript stores strings as UTF-16
(double byte) so if you want to ignore the second byte just strip it out with a bitwise &
operator on 0000000011111111
(ie 255):
'a'.charCodeAt(0) & 255 === 97; // because 'a' = 97 0
'b'.charCodeAt(0) & 255 === 98; // because 'b' = 98 0
'?'.charCodeAt(0) & 255 === 19; // because '?' = 19 39
For supporting all UTF-16 (also non-BMP/supplementary characters) from ES6 the string.codePointAt() method is available;
This method is an improved version of charCodeAt which could support only unicode codepoints < 65536 ( 216 - a single 16bit ) .
JavaScript stores strings as UTF-16
(double byte) so if you want to ignore the second byte just strip it out with a bitwise &
operator on 0000000011111111
(ie 255):
'a'.charCodeAt(0) & 255 === 97; // because 'a' = 97 0
'b'.charCodeAt(0) & 255 === 98; // because 'b' = 98 0
'?'.charCodeAt(0) & 255 === 19; // because '?' = 19 39
To ensure full Unicode support and reversibility, consider using:
'\n'.codePointAt(0);
This will ensure that when testing characters over the UTF-16 limit, you will get their true code point value.
e.g.
''.codePointAt(0); // 68181
String.fromCodePoint(68181); // ''
''.charCodeAt(0); // 55298
String.fromCharCode(55298); // '?'
To convert a String to a cumulative number:
const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0), 0);
console.log(stringToSum("A")); // 65
console.log(stringToSum("Roko")); // 411
console.log(stringToSum("Stack Overflow")); // 1386
_x000D_
Say you want to generate different background colors depending on a username:
const stringToSum = str => [...str||"A"].reduce((a, x) => a += x.codePointAt(0), 0);
const UI_userIcon = user => {
const hue = (stringToSum(user.name) - 65) % 360; // "A" = hue: 0
console.log(`Hue: ${hue}`);
return `<div class="UserIcon" style="background:hsl(${hue}, 80%, 60%)" title="${user.name}">
<span class="UserIcon-letter">${user.name[0].toUpperCase()}</span>
</div>`;
};
[
{name:"A"},
{name:"Amanda"},
{name:"amanda"},
{name:"Anna"},
].forEach(user => {
document.body.insertAdjacentHTML("beforeend", UI_userIcon(user));
});
_x000D_
.UserIcon {
width: 4em;
height: 4em;
border-radius: 4em;
display: inline-flex;
justify-content: center;
align-items: center;
}
.UserIcon-letter {
font: 700 2em/0 sans-serif;
color: #fff;
}
_x000D_
str.charCodeAt(index)
Using charCodeAt()
The following example returns 65, the Unicode value for A
.
'ABC'.charCodeAt(0)
// returns 65
Source: Stackoverflow.com